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.TH MQUEUE.H 3HEAD "Aug 30, 2002"
.SH NAME
mqueue.h, mqueue \- message queues
.SH SYNOPSIS
.LP
.nf
\fB#include <mqueue.h>\fR
.fi

.SH DESCRIPTION
.sp
.LP
The <\fBmqueue.h\fR> header defines the \fBmqd_t\fR type, which is used for
message queue descriptors.  This will not be an array type.  A message queue
descriptor may be implemented using a file descriptor, in which case
applications can open up to at least \fBOPEN_MAX\fR file and message queues.
.sp
.LP
The <\fBmqueue.h\fR> header defines the \fBsigevent\fR structure (as described
in <\fBsignal.h\fR>, see \fBsignal.h\fR(3HEAD)) and the  \fBmq_attr\fR
structure, which is used in getting and setting the attributes of a message
queue.  Attributes are initially set when the message queue is created.  A
\fBmq_attr\fR structure has the following members:
.sp
.in +2
.nf
\fBlong    mq_flags       message queue flags
long    mq_maxmsg      maximum number of messages
long    mq_msgsize     maximum message size
long    mq_curmsgs     number of messages currently queued\fR
.fi
.in -2
.sp

.sp
.LP
Inclusion of the <\fBmqueue.h\fR> header may make visible symbols defined in
the headers <\fBfcntl.h\fR>, <\fBsignal.h\fR>, <\fBsys/types.h\fR>, and
<\fBtime.h\fR>.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Standard
.TE

.SH SEE ALSO
.sp
.LP
.BR fcntl.h (3HEAD),
.BR signal.h (3HEAD),
.BR time.h (3HEAD),
.BR types.h (3HEAD),
.BR attributes (7),
.BR standards (7)
